What is the ruling on repeatedly delaying prayers, and how can one make up for missed prayers?

Prayer is a great pillar of Islam, and neglecting it is a grave sin. Whoever neglects prayer must hasten to repent and be diligent in performing it, and increase in seeking forgiveness and doing good deeds. If the number of missed prayers is known, they must be made up in order, and if it is not known, then one should continue to make them up until it is most likely that one's responsibility has been fulfilled.